Smoking costs 440,000 lives in the U.S. every year. Smokers who want to quit are often encouraged to seek social support, and formal interventions often include supportive components. Evidence for the effectiveness of socially-supportive treatments is equivocal, however, and gender has mostly been ignored as a moderating factor. Using an experimental framework, this revised application tests a model in which social support is proposed to influence smoking cessation through its ability to attenuate stress responses such as negative affect and blood pressure increases, responses that could trigger urges and lead to lapses. Moreover, it hypothesizes that the gender of the support provider and recipient play an important role in the extent to which support is effective in attenuating stress responses. Two studies will investigate the validity of this model. Both studies will examine the effects of experimentally-provided emotional support on negative affect, urges, physiological indicators of stress, and actual smoking, among adult men and women smokers who undergo a stressful laboratory task. In both studies, male and female smokers from the community will be randomly assigned to 1 of 3 social conditions to perform a stressful speech task with a supportive or neutral partner, or alone. In Study 1 (2x2x3 factorial design), the partner will be a female or male confederate. In Study 2 (a 2 x 3 factorial design), smokers' opposite-sex romantic partners will provide support. In both studies, the effects of social support in attenuating smoking following a stressor is hypothesized to be mediated by reductions in negative affect, urges, or physiological stress. Overall, these two studies will extend the literature on social support and smoking cessation by (i) elaborating and testing a model of how social support may operate to influence urges and lapses during quitting, (ii) providing the first experimental test of the effects of social support on outcomes relevant to cessation (e.g., urges to smoke, negative affect), and (iii) examining the role of gender in the degree to which urges and smoking are attenuated by the provision of support. [unreadable] [unreadable] [unreadable]